/*
 * ****************************************************************************
 * Copyright (c) 2013, Daniel Murphy All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright notice, this list of conditions
 *   and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice, this list of
 *   conditions and the following disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ****************************************************************************
 */
package org.jbox2d.callbacks

import org.jbox2d.collision.Manifold
import org.jbox2d.dynamics.contacts.Contact

// updated to rev 100
/**
 * Implement this class to get contact information. You can use these results for things like sounds
 * and game logic. You can also get contact results by traversing the contact lists after the time
 * step. However, you might miss some contacts because continuous physics leads to sub-stepping.
 * Additionally you may receive multiple callbacks for the same contact in a single time step. You
 * should strive to make your callbacks efficient because there may be many callbacks per time step.
 *
 * @author Daniel Murphy
 * @warning You cannot create/destroy Box2D entities inside these callbacks.
 */
interface ContactListener {
  /**
   * Called when two fixtures begin to touch.
   *
   * @param contact
   */
  fun beginContact(contact: Contact)

  /**
   * Called when two fixtures cease to touch.
   *
   * @param contact
   */
  fun endContact(contact: Contact)

  /**
   * This is called after a contact is updated. This allows you to inspect a contact before it goes
   * to the solver. If you are careful, you can modify the contact manifold (e.g. disable contact).
   * A copy of the old manifold is provided so that you can detect changes. Note: this is called
   * only for awake bodies. Note: this is called even when the number of contact points is zero.
   * Note: this is not called for sensors. Note: if you set the number of contact points to zero,
   * you will not get an EndContact callback. However, you may get a BeginContact callback the next
   * step. Note: the oldManifold parameter is pooled, so it will be the same object for every
   * callback for each thread.
   *
   * @param contact
   * @param oldManifold
   */
  fun preSolve(contact: Contact, oldManifold: Manifold)

  /**
   * This lets you inspect a contact after the solver is finished. This is useful for inspecting
   * impulses. Note: the contact manifold does not include time of impact impulses, which can be
   * arbitrarily large if the sub-step is small. Hence the impulse is provided explicitly in a
   * separate data structure. Note: this is only called for contacts that are touching, solid, and
   * awake.
   *
   * @param contact
   * @param impulse this is usually a pooled variable, so it will be modified after this call
   */
  fun postSolve(contact: Contact, impulse: ContactImpulse)
}
